


Through Thicc and Thin

by Moonblastbitch



Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Byleth is crazy thicc and everyone's being really extra, Consensual Underage Sex, Dimitri is suffering from an undiagnosed case of the hornies, F!Byleth, F/F, F/M, M/M, Multi, Sylvain "On god we gonna get you pussy bro" Gautier, Teacher-Student Relationship, background ashe/mercedes/annette, dying of thirst
Language: English
Status: Completed
Published: 2019-08-29
Updated: 2019-09-28
Packaged: 2020-09-29 13:30:54
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 14,680
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20436833
Author URL: https://archiveofourown.org/users/Moonblastbitch/pseuds/Moonblastbitch
Summary: Upon gaining weight, Byleth decides a change in costume is in order. Little does she know how much that will effect His Highness.





	1. Chapter 1

**Author's Note:**

> Before we get started let me please go check out @ghostpotion_art on twitter who created the design of Byleth I used as inspo for this fic. Their Byleth is absolutely incredible!
> 
> https://twitter.com/ghostpotion_art/status/1163210475892617216?s=21
> 
> This fic does contain a graphic relationship between a student and his teacher. If you feel engaging in this content will not be good for your mental health please feel free to click away. Otherwise, please enjoy my fun little tale!

Working at the school had been a blessing in Byleth’s life. After years of traveling across the land with her father, never knowing when they’d get their next meal, living somewhere with food at the ready and a warm bed every night was a luxury she’d never tire of.

One thing she hadn't expected however, was how limited physical activity and regular banquets would change her body. After over 20 years of non-stop combat, the respite of being a professor was causing certain parts of her body to soften.

As she struggled to pull up her tights Byleth heard a large rip coming from her derriere. Huffing, she tore the hosiery off and began looking through her closet. Choosing clothing had never been on the forefront of her mind, but she made a quick mental note to herself to run to the market after classes ended. She’d need to get herself measured as well. 

Byleth glaced at herself in the mirror. In the past eight months since coming to the school her hips had expanded greatly, along with her thighs. She gave herself an experimental poke in the stomach, which had grown soft and malleable. Never one for vanity, Byleth shrugged, pulled on the shorts she normally wore with her work uniform and rushed out the door.

By the time she had gotten to her classroom all of her students had gathered at their desks. Ashe and Annette were sharing today, giggling over some book one of them had brought. Mercedes kept glancing at their table, seemingly troubled, while Dedue sat next to her in quiet contemplation. Sylvain, Felix, Ingrid and Dimitri were grouped together as usual, and appeared to be in a heated discussion. The only one who actually seemed to pay attention to her walking through the door was Flayn.

“Oh my professor, good morning!” She said with a bright grin. Byleth gave a smile back as she walked to the center of the class. For whatever reason, a hush fell upon the room. Normally her entrance didn't call for a silence, quite the opposite in fact. By this time the students would be lining up at her podium, innondating her with questions. But for whatever reason today they were all quiet.

Byleth set down her things and turned around. Her students stared at her with wide eyes. Maybe they thought since she was running late today class would be canceled? It wouldn't be the first time someone (Sylvain) suggested they all leave when she was gone from the hall for more than a few minutes.

“Woooooow teach, I’m digging the new look.” Sylvain exclaimed from his reclined position at his desk. Ingrid quickly smacked his back, forcing him to sit up straight.

“My apologies professor, please ignore his comments on your appearance.”

Byleth looked down at herself quizzically. Other than her tights this was the same outfit she always wore. But then again Sylvain was known to take any opportunity to flirt, so she chose to ignore it. In his seat right in front of her she saw Dimitri cough into his hand. He looked a bit pink.

“Dimitri are you not well? Would you like to visit Manuela in the infirmary?”

The whole class began to snicker, and Sylvain clapped his friends shoulder from behind. Quickly the house leader stood up.

“I’m well thank you. I apologize for being a disturbance.” He said with a bow.

Byleth stared at Dimitri as he sat back down. While she had been told it wasn't wise to pick favorites, Byleth had a special place in her heart for him. He was sweet and helpful, but known to bottle things up. Before he had the chance to protest she walked over to him and put a hand on his forehead.

Dimitri stared up at her dumbfounded, his cheeks still flushed. Out of the corner of her eye she could see Felix rolling his eyes. 

“Professor he’s fine, lets just get on with the damned lecture.”

Byleth sighed and removed her hand. He didn't feel feverish, just warm. “Let me know if you need to leave for the day.” 

“O-Of course. Will do.”

Once the class settled down she began her lecture for the day. Each day she tried to work a specific weapon into the frame of the classroom lecture, to allow those who don't normally prefer that type to get in some practical experience. Once they concluded with the logistics training, she had everyone line up outside of the classroom to practice lances.

“Alright everyone please pay attention.” Byleth announced to the class. Looking around she could see some of the students, specifically Annette and Mercedes, look skittish at the idea of using weapons. Last time Mercedes tripped and nearly took out her own eye, were it not for Dedue stepping in and pulling the weapon away from her. Perhaps a classroom demonstration would make them feel more at ease.

Byleth turned her body to the starting position, holding the training lance tight in her grip. 

“Typically in combat lances are used to hold the line so to speak. They’re a powerful and versatile weapon, but take years of dedication to master. We’ll start by demonstrating some basic maneuvers and then move to defensive tactics. Before we start does anyone have any questions?”

Surprisingly Sylvains hand was the one that shot up. Byleth couldn't help but wonder why he was so active in class today.

“Teach, not that your lance skills aren't something to behold, but wouldn't it be better if we saw someone who was a master at the lance demonstrate? Like His Highness for example?”

Dimitri whipped his head around, glaring at his best friend. 

“That's an interesting idea Sylvain. But could you explain to me how seeing Dimitri wield his lance would help you more than myself?” Byleth asked

“Well…” Sylvain mumbled.

“If we see the boar in action you can point out to us what he does wrong.” Felix said, a bored tone to his voice.

“I see. Dimitri, if you please.” Byleth asked, motioning for him to come to the front of the class.

He hesitated, but eventually trudged his way up, training lance in hand. “I’d be happy to professor.” He gritted out. From the back of the classroom Byleth could see Sylvain grinning ear to ear.

“There we go. Please go into front stance.” She asked her student. As expected, he fell into place perfectly. 

“Beautiful.” Byleth said with a smile. Dimitris face began to flush again. His grip tightened on the shaft of the weapon.

“Alright everyone follow along. Dimitri please move into a lunge stance.” Strangely this time his footing wasn't quite right, and he seemed to be holding onto the lance for dear life. Byleth frowned.

“Now now, loosen up a bit.” She asked, placing a hand on his arm. He nodded his head and corrected his stance. The class followed suit.

“Next up is an attack stance.” Byleth said as the prince next to her moved into the forward motion. She noticed his arms were shaking a bit, and his hold on the lance was starting to slip. Quickly, the professor moved behind him to fix his position.

It was harder than it looked, Byleth wouldn't normally consider herself small, but next to Dimitri everyone looked tiny. She stood on her tip-toes and pressed herself against his back, wrapping her arms around his so she could fix his grasp. A strange squeak came from him as she put her hands over his.

“I’m sorry, did I startle you?” She asked, a questioning expression on her face.

“No. No no no! Not at all professor. I think.... The heat! It's just been getting to me. Or maybe the temperature change? No matter! You may have been right at the start of the class. I think I am coming down with something. May I be excused?” Dimitri asked her, talking so fast she almost couldn't understand him.

Poor thing. She should have tucked him into bed herself. Of course Seteth would probably get on her again for “inappropriate behavior towards the students”, whatever that was supposed to mean.

“I’ll walk you over there myself. Ingrid, would you like to lead the class in my absence?” Before she could respond, the prince interrupted.

“No I would hate for everyone to have to miss out on the lecture because I became ill. Please continue, I’ll walk myself over.”

Byleth frowned, concerned for her pupil. “If you think that's best. I’ll come by later to check on you.”

“Ah, yes. Thank you professor. I’ll be on my way.” He said with a smile, walking off in the direction of the infirmary. Byleth couldn't shake the feeling that something else was wrong with him, but tried to ignore that as she continued her demonstration. After all, if he had a problem he would just come to her.

Right?

Dimitri Alexandre Blaiddyd had survived fire, famine, pestilence and plague, but nothing had felt as challenging as this morning. He felt his blood rush to his loins just thinking about it.

Today was supposed to be normal. There were just a couple more weeks until the ball, school was going well, for the first time in years Felix seemed to be warming up to him, everything was nice. Then the professor walked into class.

It was no secret amongst their friends that Dimitri had something of a crush on the instructor for the Blue Lions. Sylvain teased him about it constantly, Ingrid gave him advice on how to dictate himself in a ‘well distinguished but interested manner’ (whatever that was supposed to mean) and Ashe had even loaned him a book entitled “The Many Wives of King Garrus” which supposedly contained romantic advice. It was only a matter of time until the entire academy knew of his feelings.

But he’d kept them… relatively under control until today. Then their teacher chose to walk in with bare legs and all his well curated manners went out the window. He couldn't help it! His eyes were trained on her body the second she walked in. He thought his desires would fade when she went behind her podium but no! His loving, wonderful professor stood right in front of him and measured his temperature for the whole class to see. He’d have those smirks burned into his brain until his dying day.

But her hands were so soft! And warm! He wanted to lean into it so badly. Would have, if not for the whole class watching. And with her that close her chest was right in his eyeline. He felt so guilty for the way his hands itched to touch her. He could feel her stare bore into him with a look that would surely come back in his dreams.

It would have been fine. After that he was able to sit down, recollect himself, wait for the pressure in his groin to subside, but he had forgotten that today was a demonstration day as well. And only a short lecture later they were outside, where a new round of torment had begun.

He was going to kill Sylvain the next time he saw him. He knew exactly what he was doing volunteering him like that. And Felix had even encouraged it! What, were all of his old friends now conspiring to expose his crush?

But the second her arms wrapped around him Dimitri thought he’d been transported to the heavens. The way her body brushed against his was exactly how he’d fantasized for the past nine months. He shook himself from his stupor. He was a five minute walk from the infirmary, but he certainly wasn't ill. Since classes would be going on all day he wouldn't have to worry about someone coming to speak with him in his room. Which meant he had plenty of time to get himself in check before anyone came looking for him.

Determined, Dimitri turned around and matched back to the dorms, carefully going around the courtyard where the rest of the Blue Lions were practicing drills. After what seemed like an eternity, he marched into his room, flipping the lock and stripping out of his uniform.

When he first touched himself while picturing his teacher he felt so guilty he couldn't look at her the next day. Then she’d leaned over his desk to help him with a logistics problem, giving him an eyeful of cleavage in the process and he was pawing at himself yet again. For months he’d been doing this, and what was once relief had evolved into torture.

Dimitri grasped himself in his hand, not even waiting to crawl onto his bed before rolling his hand up and down his shaft. He looked around the room frantically for the lotion he’d gotten from the market last month. He bought the largest container possible and he’d still managed to use half of it in the intervening time.

Quickly he slathered his hand and got to work, rubbing himself fiercely against his palm. He thought of his sweet, wonderful teacher and her wide hips that he just wanted to paw at like a beast. He thought of her warm heavy breasts that he would bite the second she gave him the opportunity. 

He dove head first into the bed, rubbing himself to near pain. He tried desperately to recall the smell that filled his senses when she got behind him to correct his posture. What he wouldnt give to be able to embrace her, to hoist her onto the closest surface and fuck her into oblivion. What noises would she make? The Professor was not an expressive person, perhaps carnal pleasure would be the one thing to break her eternal poker face.

Her voice echoed in his head as he began to thrust faster into his hand, egged on by the ghost of her touch. She was the only one who called him by his name with no title attached. He remembered once running into her in the library late at night with Dedue. Her voice was tired and soft, exactly how he thought she’d sound if she’d woken up next to him. He felt the build up of desire crest inside of him. He grabbed one of the pillows next to him, burying his moans inside the goose-down fabric as he came all over his stomach.

Dimitri looked down tiredly at the cum that dripped across his body. When he got up to wipe it off of himself a knock came at the door. He jumped. Did the person at the door hear him groaning with ecstasy?

“Dimitri? I’m here to check up on you.” The object of his obsession said through the heavy oak.

He felt panic begin to stir inside of him. He needed to change into something respectable, and clean himself quickly.

“Ah yes Professor. Sorry I was just… napping. I’ll need a few minutes to dress, if that's alright.”

He was met with silence, which he hopped was a sign the professor was agreeing with him, not fumbling for her master key. Just in case he dressed himself quickly in the clothing he wore under his uniform, a black turtleneck sweater and dark trousers.

He flung the door open, to the surprise of Byleth who looked up at him with her head tilted. It was such an adorable expression the prince had to pinch himself to not allow his mind to wander further. “How may I help you professor? I thought classes were ongoing until the final bell?”

His teacher frowned, pushing into his room. Dimitri panicked. Did he leave anything conspicuous out? The only thing of note was the towel he used to clean himself with but it didn't reveal anything hanus. He felt his face flush as his eyes darted across his room. 

“Why aren't you in the infirmary?” Byleth asked, worry laced in her question.

Dimitri relaxed. Of course she was just concerned as an educator. She had given him specific instructions afterall. “I apologize. I knew Professor Manuela wouldn't be back for at least an hour so I just went back to my quarters to rest. I hope that's okay.”

The Professors normally blank expression twisted into unease. She laid her hands flat on his chest and Dimitri felt his heart jump to his throat. Was this? Was she?!?!

“Lay down.” She ordered, gently pushing him onto his bed. Dimitri, feeling boneless and pliant, obeyed. 

“Are you still having difficulty sleeping through the night?” She asked, sitting next to him.

Ah. She just wanted to make sure he was sleeping. Dimitri tried not to be disappointed, but it's not as if this was a surprise. No way would his responsible Professor stoop to sleeping with a student.

“Uhm. Yes I suppose. It's gotten better lately though.” That was a lie. Just add it to the list of things he was keeping from her.

“Good.” She said softly above him. She moved her hand to his forehead, as she had several hours earlier. Dimitri relaxed into her palm. He felt the desire to rub into her hand like a kitten. Soon her hands moved from his forehead to his hair, and gently began carding her fingers through. 

“You’re sticky.” Byleth whispered above him. He jolted up. Had he forgot to clean something? Had some of his cum stuck to his forehead somehow? God no, now she’ll find out he’s a secret deviant.

“Ma’am I’m so sorry for my lack of grace!” He exclaimed, red and wide eyed.

“Why?” She asked, tilting her head in that adorable way that made him want to wrap her into his arms and keep her there forever.

“I… I just… I should have cleaned myself properly before your arrival, I know that's incredibly tasteless of me.” He said, floundering for an appropriate way to apologize for ejaculating to the thought of shoving his head into her breasts.

“Dimitri, your sick. I’m not offended that you’ve been sweating.” She said comfortingly, patting his head.

“Sweat… Of course, yes, sweating! I… I’ve just been raised to always maintain cleanliness. That's all.” He said, thanking the goddess for his teachers denseness.

“Its alright. I need to run some errands this afternoon. If you’re feeling better would you like to have dinner with me tonight?” 

“Ah! Yes I would love to Professor!” He exclaimed, trying (and failing) to not look down his mentors shirt while she leaned forward.

“Then I’ll see you tonight.” she smiled, picking herself up and going towards the door.

Dimitri wanted to celebrate. He’d made it through an entire one on one with the Professor without once getting an erection. Sure it had only been a few minutes but that was a new record.

And then Byleth bent over and his record was swiftly smashed. He stared dumbly at the curve of her behind as her shorts bunched up around her stomach. Her thighs looked so round and perfect, he had to sit on his hands to resist the urge to grab at her.

“Whats this?” She asked, standing back up with the lotion that he’d flung aside.

“Oh… uhm that's my…”

“I have the same one. I use it for my muscles after a long day of training.” Dimitri gulped, he could just imagine her rubbing that thick white cream all over her legs. He wanted to scream in agony.

“I…. I use it for the same! It's very helpful.” He added, trying and failing to keep the conversation innocent.

“Mhm. Well I’ll be going now.” His teacher said, handing the container back to him and exiting his room. 

Dimitri waited, paralized that she might think of something else and come back. He looked down at his crotch, which was already swollen with desire.

“God damnit.” He sighed, falling back in the bed, using his teachers visit as inspiration for his next masturbation round.

Byleth tugged uselessly at her shorts. She should have went right to the market after class but she was so worried for the young prince. He looked so distraught during class. She still had the image of his face twisted in pain burned into her brain. She had a sneaking suspicion he’d been hiding something from her when she stopped by his room.

Right before she knocked she heard a powerful low groan. She was ashamed to admit that noise made her whole body pulse. But he was in pain and she was not about to let him suffer alone. So she ignored her own desires and knocked on the door. He’d answered the door in a panic, his face glowing with sweat and his body taunt. 

As usual, her beloved pupil was not giving anything away. He had skillfully hidden his pain from her, even when she’d inspected him personally. All she could tell is that he was hot and restless. Then she’d seen the lotion. And she knew exactly what was bothering him. He must have pulled a muscle and was too embarrassed to tell anyone!

That would be very like him she thought to herself while she walked past the entrance guardsmen, who shouted out a “Greetings Professor, nothing to report!” behind her. 

“Hiiiiiii Professor Byleth!” A flirty voice said from one of the stands. She turned around and saw Anna, one of the merchants that visited the Monastery’s marketplace regularly. She was chatting with Dorothea, who was looking over some of the jewelry that was displayed.

“Oh Professor hello! What brings you to the market today?” She asked. 

“Hi. Could I get measured for some new clothes?” 

Anna and Dorothea looked at each other, then in unison asked. “Clothes?”

“Yes. I’m too big for my old uniform.” Byleth said matter of factly.

“Oh I’m so jealous Professor! I’ve been trying to put on weight for the past year! No matter how much bread I eat I never seem to gain more than a couple pounds!” Dorothea squealed.

“Yes, you know fat is quite attractive these days Professor Byleth. I can have some clothes ready for you by tonight if we measure you now.” Anna said.

Byleth blinked. “By tonight? Doesn't custom clothing usually take a week?”

“Oh yes, but three of my sisters came with me and they’re itching for a task.” Anna said. “Plus you’re one of my most loyal customers. Now let's talk design, what would you like?”

“... The same?” Byleth said. Her last set of clothes had been picked out for her by a friend of her father’s from their mercenary days. As long as they fit and they functioned she didn't particularly care about fashion.

“Oh Professor thats no fun!” Dorothea protested. “I have an idea. Let me and Anna design something for you. I promise you that you won't be disappointed.”

“Oooooh that sounds like a riot!” Anna said, bouncing happily.

“... Are you sure?” Byleth asked.

“Of course Professor. It’s a thank you for helping out my Ingrid so much.” Dorothea laughed.

“And if you don't love it I wont charge you. So do we have a deal?”

“Yes. That sounds fine.” Byleth agreed. 

“Awesome, alright professor, let's get you stripped and into the changing tent, I’ll measure you out.”

After a bit of poking and prodding, with lots of comments from Dorothea, Byleth exited the tent. Anna and her three identical sisters (who also called themselves Anna) had been so excited by the prospect of a challenge they’d closed the shop for the day, demanding that she come back in a few hours and pick up her new uniform.

That left Byleth free until dinnertime, so she quickly busied herself with small errands. She picked up chamomile tea from the eastern merchant, had several weapons repaired, did some fishing and walked over to the garden to harvest the vegetables she planted a few weeks ago. As she walked inside, she noticed that the usual attendant was absent. Then she heard a giggle break out.

“A-Annette, come on, we’re gonna get caught.” A voice that sounded suspiciously like Ashe said somewhere in the building. Byleth hid near the door. What exactly were her students up to?

“Shhhh its okay! No one but Dedue comes in here, and that's only in the morning.” Annettes voice said, followed by a loud sucking sound. Oh dear Byleth thought.

“Ah- I just AH, Ann-” Ashes voice was cut off. That was enough of listening in. Byleth rubbed her temples, sneaking away from the Greenhouse. She put ‘talk to Annette about contraception’ on her mental to do list.

As she walked away Mercedes bumped into her. “Oh Professor! I’m sorry.” She said, clearly distracted.

“It's fine. What's wrong Mercedes?” 

“Oh. I just was trying to find Annie. We got in a fight a few days ago, I… I wanted to apologize.”

“She's a bit occupied right now.” 

“With what? Studying?”

“With Ashe actually.” Byleth regretted saying that once it left her mouth. Mercedes went white as a ghost.

“Oh. I see.”

“Mercedes would you like to talk about it?”

“No. Its fine. I’m fine.” She said that, but Byleth could see the tears beginning to well up in her eyes.

“How about we just go drink some tea? My treat.”

“That… That sounds lovely Professor. Thank you.”

A few minutes later and Byleth was pouring tea for Mercedes, who was looking off into the distance.

“Why did it have to be Ashe Professor?” She asked softly.

“What do you mean?”

“Its… I just. I know Annies closer in age to him. I knew they got along well, they started studying together recently. I just didn't think they be spending so much time together. You know?”

“Tell me the whole story.” Byleth might be a rookie teacher, and have about as much social awareness as a puppy, but she was a damned good listener.

“Well… About a month ago I started getting cooking lessons from Ashe. It was really fun at first! But he started asking all these questions about Annie. Like the kind of tea she liked and her favorite color, stuff like that. I didn't think anything of it at the time, I just figured he wanted to be friends with her! So I suggested he ask her for help with studying so he could get to know her. And then… Then he did.”

“And you miss her?”

“Yes. It's not just that. Everytime I go to see Annie, Ashe is there. If I want to eat dinner with her or go shopping with her she's always asking Ashe if he wants to come along too! We finally got the chance to go shopping together when Ashe was busy practicing swordsmanship with Felix and all she could talk about was him! So I got mad. And we fought. And now..”

“Now she and Ashe spend even more time together?”

“Yes! And I don't know what to do! I miss her so much, and I’m so… so jealous! And I’m mad at myself for not talking to Annie about my feelings. I mean how can I blame Ashe for falling for her? I feel the same way.”

Ah teenagers, Byleth thought to herself. Luckily Mercedes didnt put up walls like her fellow classmates did. It made diagnosing the problem much easier. “Why don't you speak to Ashe instead of Annette?”

“Ashe?”

“Well if he’s always with her why don't you ask him for help? You three should sit down and talk. Annettes just excited about having a friend. You just have to tell her you miss her and I’m sure she’ll make time for you.”

Mercedes looked lost in thought. “I suppose it's worth a shot. Thank you Professor. I’m going to go help with getting dinner started. I think Ashe is scheduled for tonight too. I’ll talk to him.”

“Good luck.” she said to her students as she walked to the dining hall. The bells chimed, signifying that dinner would be in fifteen minutes. Byleth got up, packing away the tea kit, and walked over to the marketplace.

Before she even exited the entrance hall Dorthea grabbed her by the arm. “Oh Professor just in time! Come quick, look at our masterpiece.” She sang out, pulling Byleth to the changing tent she’d been in earlier.

“No time to lose, try this on.” Anna said, throwing some kind of body suit at the instructor.

“Is this my new uniform?” Byleth asked, holding the suit in front of her.

“Yes silly! Now try it on! There's some other accessories to go with it that we’ll help you with after you’ve changed.” Before she knew it, one of the Annas started stripping her of her boots, while another Anna was working on her top.

“Sorry Professor Byleth! My sisters are just so excited to see you in their latest creation.” Anna explained with a wide smile across her face. The sisters hurriedly dressed her in the suit, zipping it up behind her.

She looked down at herself. The bodysuit was… snug but comfortable. A lot warmer than her prior uniform, which would definitely come in handy as fall turned to winter. 

“Alright, and don't worry we thought practically, we have some armour for you!” One of the Anna’s said as they started equipping it onto her person.

“As you can see it clips right on like so, which’ll make it easy for when you get dressed alone. Plus we got you some boots! And a corset for your waist!”

“A corset?” Byleth had never worn a corset before. The times when she’d asked Jeralt about it he just sighed and said, “We’ll get you one when your older.”

She was fairly certain he was too embarrassed to shop for one with her. The third Anna wrapped it around her waist.

“Do you need me to take the suit off?”

“Oh no, this is a newer style. Its meant to be worn on the outside of your clothes as an accessory. Cool huh?”

“Alright girls, let's add the finishing touch.” Anna said, and Dorothea came out with a flourish, holding an impressive looking black cape.

“This was my idea.” she giggled, attaching the fabric to Byleth’s shoulders.

“Annnnnnd its done! Look at yourself! You’re gorgeous!”

Byleth turned around and looked at herself in the mirror. She looked nice. Attractive even. With the corset on her breasts were pressed up higher than usual, but it complimented her shape nicely. And the black color scheme made her tanned skin pop. It made her feel pretty. For maybe the first time in her life. Soothis cooed compliments from inside her mind.

“Well well well, you’ve been busy while I’ve been resting haven't you? You look quite darling. Getting dressed up to meet your handsome prince for dinner I see.” She said smugly. Soothis had been teasing her for the better part of six months for her attraction to Dimitri, which Byleth had been deftly dodging. 

“Anna this is…. So nice. What do I owe you?” Byleth asked, not being able to suppress the urge to smile.

“You just paid it Professor.” Anna said. “Consider the outfit yours.”

“Oh Professor you must ask them to make you spares, just in case you tear up this one.” Dorothea mentioned.

“Ah… yes that's a good idea. May I pay for about four extra suits then?” 

“Of course. We’ll have them ready for you next week when you stop by on your errands. Now run along you two, we must close up shop.”

“Professor, would you like to walk to the dining hall with me?” Dorothea asked. Byleth nodded and the two walked together.

“You know, everyone is going to be so stunned when they see you!”

“I guess they have never seen me wear anything else.”

“No Professor! I mean everyone is going to fall over flat! You look so good! You’re gonna break a lot of hearts you know.” She teased.

As Byleth was about to protest the pair walked through the doors to the hall. The cacophony of the dining hall was always a comfort to her. Tonight it was especially buzzing with everyone discussing the dance competition that was to take place next week. As Dorothea excused herself to sit with some of the Black Eagles, Byleth started looking for Dimitri.

There at the corner table was the leader of the House of Blue Lions with his back facing away from her, in a heated discussion with Sylvain and Ingrid. Unsurprisingly, it was Ingrid who looked up first, and who with wide eyes waved their professor over.

Both boys turned to welcome her. First was Sylvain, who took one look at her and then turned to grin a cheshire cat grin at his prince. Dimitri turned around in his seat to see her and his jaw promptly dropped.

“Pr-Professor.” He stuttered out, standing up to greet her. Byleth smiled at him and sat down with her students.

“Hello. Have you all caught up on your class assignments?”

“Woah woah woah teach, you want us to discuss classwork when you look this good?” Sylvain asked, earning a smack in the back of the head from the girl next to him.

“That's enough. To answer your question, I made sure that the three of us finished all our assignments, and we just wrapped up with stable duties for the night. It's been quite the productive day, wouldn't you say Your Highness?” 

Byleth glanced at Dimitri, who was seemingly shocked into a stupor. In response, she reached up to feel his forehead once again. Unbenounced to the Professor, Ingrid and Sylvain gave each other a knowing look.

“Are you sure you wont go see Manuela?” Byleth asked, satisfied that the prince wasn't feverish.

“Ah.. no I don't think I need to. I suppose it's just been quite a day. I’m sure I’ll be better in the morning.”

“Oh yeah, take my word for it, His Highness has been having these fits for the better part of the year. Since you showed up at le- OW.” Byleth heard the table rock underneath her. Apparently Sylvain earned his princes wrath with that last comment. 

“Lets not worry her over something miniscule shall we.” Dimitri said with a friendly smile.

“I agree. So what shall we be having for dinner tonight?” 

From there the conversation began to flow. Ingrid and Sylvain made wonderful dinner company, and even Dimitri, who was more quiet than usual, became animated as the night went on. Eventually as more people filtered through the dining hall Dedue joined them.

“Professor, might I ask what the policy is for students being caught in…. Acts of intimacy?”

Sylvain began to chuckle uproariously, while Ingrid and Dimitri seemed to choke on their food as Dedue asked the question.

“I’m not positive there is a policy in place. Why do you ask?”

Dedue sighed and scanned the dining hall, then motion towards his left, where Ashe and Annette were sharing a meal and giggling. “I caught the two in a rather... compromising position. It may be pertinent to have a discussion with them soon.”

“No way!” Sylvain said in between bursts of laughter. “You mean- Ashe? And Annette?”

“Please be sure this does not leave the table. I would hate to have either one suffer unnecessary repercussions for this.” Dedue said, looking directly at the red head.

“I’m sure it's just a misunderstanding! There's no way Annette and Ashe of all people would…” Ingrid trailed off, looking over to the table next to them as Annette said something that made Ashe go redder than her hair.

“I’ll be speaking to them after class about family planning.” Byleth said as she finished off the last of her stew.

“So… You’re not upset with them?” Dimitri asked cautiously.

“What's to be upset about?”

“I mean. They were behaving in an- excuse the euphemism- lewd manner. That sort of thing is usually not taken lightly in Fodland.”

Byleth tilted her head curiously. “There's no use punishing them for something we’ve all done at one time or another.”

Strangely the table was silent at that. She looked at the faces of her students, who all looked uncomfortable with the subject change. Oh. 

Dimitri was the first to break the spell. “Well… that's admirable of you professor. Will you excuse me, I’m going back to my room to rest. I look forward to training with you tomorrow.” He said, swiftly gathering everyone's dishes and bringing them back to the kitchen staff.

“His Highness has been under a lot of stress you see.” Dedue said apologetically.

“Stress? Is that what we’re calling it these days? Funny word for crushing desire.” Sylvain said. Ingrid moved to punch him, but he quickly got out of his seat and moved behind her.

“Uh uh uh, C’mon Ingrid, I’ll walk you back to your dorm, Night Professor.” He said, cheerfully pulling his companion along with him.

“Sylvain!” Byleth heard her student call out as she was being dragged away. Those two had the strangest relationship, she thought.

“Is there anything I could do to help?” She asked Dedue.

“Perhaps if you spoke to him one on one more often. He always enjoys spending time with you.”

“That's simpler than I’d hope. But I’ll make time.” Byleth looked up and saw Ashe and Annette walking out into the tea gardens.

“Will you excuse me?” she asked. The boy from Duscar nodded and Byleth quietly followed after her students.

The sun was setting as she exited the hall. It gave the whole monastery a warm glow. Quite a romantic setting, she mused to herself, keeping an eye on the two holding hands in front of her. When Byleth was sure no one else was around she called out to them.

“Ashe, Annette, may I speak with you for a moment?”

The twosome turned around, separating their hands, guilty blushes covering their faces. Byleth sighed and steered them over to one of the sitting areas in the gardens.

“Hi Professor! What can we help you with?” Annette asked nervously, gripping the fabric of her uniform skirt as it bunched up around her knees.

“Do either of you know what contraception is?” She asked, point blank as usual.

The guilty flush upon their faces grew brighter. Well they certainly knew what it was.

“I- Uhm- I-” Ashe stuttered, looking hopelessly at Annette for guidance.

“Relax. This isn't a lecture, nor is it a punishment.” Byleth said, keeping in mind what Dimitri had mentioned about conservative Fodland ideals of sex. “I just need to know if the two of you are safe when you fornicate.”

“WE HAVEN'T DONE IT YET” Annette yelled, clamping her hand over her mouth as soon as she said it. Ashe looked to the sky, as if wishing the goddess would strike him down then and there.

“That's alright. But when and if the moment happens will you be prepared?”

Ashe took Annette's hand. “We’ve both researched the subject thoroughly! I can promise you that neither of us will do anything that could hurt our futures.” Annette looked up at him with watery eyes.

Byleth smiled. The two might be a little green when it came to matters of the heart, but at least they cared for each other.

“That's good then. Do either of you have any questions?”

“Uhm. Yes! Professor… Is it… Uhm.. I know the school has rules about boys and girls being alone in each others rooms. Exactly how much trouble would we be in if we got caught staying the night?”

“Annette!” Ashe exclaimed.

“I’m just asking as a cautionary measure!”

Byleth sighed. No one told her this would be apart of her role as Professor. “You’ll likely be assigned to detention, and receive a stern talking to by Seteth. But otherwise you’ll be fine.”

“Ah. Alright I’m good then.” Annette said happily, getting out of her seat with her boyfriend in tow.

“Uh! I’m sorry Professor! Thank you for speaking with us!” Ashe said as Annette giggled and pulled him away.

They were just as strange as Ingrid and Sylvain. Byleth thought. 

She sat in the gardens for a few more moments, enjoying the evening breeze. Dimitri likely pulled a muscle and was treating it himself so he didn't burden anyone. But she knew without proper care such a problem could develop into a hernia and nearly criple the young prince. Someone needed to save him from being reckless with his own health. It should be her.

Byleth got up and began walking to the dorms. It was three hours until the students were corralled back into their dorms, so most of them were taking advantage of the free time. Felix, Sylvain and Ingrid were outside the Blue Lions Hall, Sylvain lounging on the grass while Ingrid and Felix sparred. Ashe and Annette apparently relocated themselves to the pond, sharing a book on one of the benches. Surprisingly Dedue was not with the prince, but rather outside his dorm meditating. He nodded at her as she walked by.

The nobility dorms were a ghost town, with only one of the stray cats that flooded the monastery to reveal any signs of life. Until she got to Dimitris quarters, where outside the door she heard a familiar moan. It made her insides spark. 

Many times while she’d been teaching the Blue Lions she’d been struck with a similar feeling. The Princes grunts and groans fell like velvet onto her ears, pooling desire into her belly. She knew it was cruel, to just stand outside his door, listening in when she should be helping her student deal with his injury, but she could not will her body to move.

Another moan rang out against the walls and Byleth rubbed her thighs together fruitlessly. She wanted to yowl like a cat in heat. But she steeled herself and knocked on the door. “Dimitri, may I come in?”

The Professor could hear a loud crash coming from the other side of the door. Just what had he been doing in there? “A-ah Professor! Yes… I… I need a moment.”

No way was she about to let him hide his injury from her. She went for the doorknob, but before she could open it, the young prince did for her. He was dressed in loose clothes, likely his pajamas. The shirt was cut at his arms, and Byleth wanted nothing more than to feel them wrapped around her.

“I apologize! I was- Well I mean.”

“Dimitri. Show it to me.”

“... I’m sorry what.”

“You heard me.” Byleth said, arms crossed underneath her breasts, attempting to give herself a no nonsense demeanor.

“I’m afraid I don't know what you mean Professor.” He said nervously.

“Yes you do, show it to me.” Byleth said, pushing herself into the room much like she had earlier in the day. 

The room was much messier than it had been. Towels were strewn about on the floor, clothes haphazardly dropped in piles, and the sheets on his bed twisted up. 

“I’m sorry for the state of my room… I was not expecting company.” He said, frantically picking up items left upon the floor and moving them to a basket tucked into this closet.

“Dimitri. Please look at me.”

Her student turned around to look at her. He had the same rosey pallor he’d had since this morning, and his posture was ramrod straight. Byleth removed her gloves and began poking at his stomach.

“Uhm…” Dimitri whispered, letting out a long, strained breath as she ran her hands up his pectorals.

“You hurt yourself didn't you?” Byleth asked as she continued her exploration. Dimitris squirming got worse and worse by the minute.

“I… ah… I’m not… sure your meaning.”

Instead of responding Byleth dropped to her knees, earning a squeak from her student. She grasped at his calves, noticing how tight and muscular they were. She massaged them with her fingers for probably more than what was strictly necessary, but she reasoned it as just being thorough.

Above her Dimitri was shaking like a leaf. She must be getting closer to his problem area. She moved her hands up to his thighs, which were just as packed with sinew as the rest of him. She resisted the urge to rest her head on his lap, pressing herself against him like an adoring kitten. 

Byleth was stumped. She couldn't find an issue with his chest, arms, or legs, She rose from her kneeling position and before she could fully pull herself up, she came face to face with the ‘problem’ her dear student was having.

“Oh.”


	2. Part Two: Down With The Thiccness

**Summary for the Chapter:**

> Now privy to the problem her favorite student is suffering from, Byleth feels compelled to help.

**Notes for the Chapter:**

> OKAY EVERYONE HERE WE GO WITH THE PORN!!!!!! Its my first time writing smut in a while and I was very nervous editing, but I think I've done a pretty good job. I wanted to thank all the wonderfully engaged commenters on this fic, it really just melted my heart. As a thank you to everyone who left kudos and sweet thoughts, I've gone ahead and finished this chapter waaaaay ahead of schedule. Thank you all so so much.
> 
> Oh and to anyone under the age of 18, this is where the smut starts. I trust that everyone will read responsibly, and if anything I've written is too graphic please click away with my blessing. Its most important that you take care of yourself and your mental health.
> 
> With all that out of the way, please have fun!

He thought he had this under control. At least enough to go to dinner with her and not make a complete fool of himself. But no. The Professor apparently decided her bare legs weren't good enough to torment him. She upgraded to a damned jumpsuit.

Sylvain had tormented him endlessly at the dinner table about the Professor stepping out of class for a few minutes to go see him. Even Ingrid got in on the teasing! But he’d kept his emotions in check, just enough so that when the Professor joined them he’d behave like the well mannered prince he’d been groomed to be.

But then she’d arrived, dressed in a tight black thing that hugged her curves in such a way Dimitri wanted to kneel in worship. Her usual outfit, while fitted, was buttoned up to a certain degree. It… left things to the imagination. The same luxury was not afforded to her new look.

Dimitri spent most of dinner trying, and failing, to hold back from staring at his instructor. The corset she now wore enhanced his lust, lifting her lush breasts right into his eyeline. All he had to do was look down and he’d be blessed with soft, beautiful flesh that ebbed and flowed with her breathing. 

His table companions took turns giving him looks. Ingrids of stern disapproval (though he certainly noticed her eyes fall south a few times) and Sylvains of what he lovingly called ‘wingmanning’. It didn't help that he and the Professor sat close together on the bench, and even the slightest brush from the woman next to him left him gripping the table for dear life. Before he left he noticed the shape of his fingers permanently indented in the wood.

Dedue gave him a look that made him want to shrivel up and die. 

And of all topics to divulge at the dinner table his most trusted companion brought up sex! And not only did his Professor react without a worry, she let all of them know she was plenty experienced. Of course she was older, it wasn't unreasonable to think she’d had a few rolls in the hay, but that information stuck to Dimitri like honey. His mind was filled with images of the mighty Ashen Demon giving him a personal anatomy lesson.

All of that made it unbearable to sit next to her any longer. He felt like a beast on a leash, if she gave even the slightest tug he would pin her to the floor and rut into her in front of the whole student body. The thought shamed him, and he quickly departed the dining hall to alleviate himself in private. 

He’d made it back to his room soon enough, eager to give himself another flagellation. He’d already brought himself to climax twice today, and the fierce rubbing gave his cock a sweet tenderness that felt eerily good inside his trousers. He threw off his clothes with reckless abandon, eager to rid himself of this demon.

He ran a hand experimentally up the length of him. He was sore but his desire far outweighed his pain. Perhaps being inside something wet and warm would relieve the sting, he thought perversely. He grabbed the lotion that sat innocently on his desk and lathered himself again, letting out an agonizing groan into the room.

He shoved his free hand over his mouth and waited for someone to knock, but remembered everyone else wouldn't be returning to the floor for another few hours or so. He indulged himself in another loud moan. And another. And another. Again and again as the raw exterior of his cock gave way to such delicious pleasure that he was practically thrashing against his bed. He had to be careful he knew. He was already on his third bedframe of the school year.

He felt his Professor’s name on his lips, just as he began to climb to his peak. Then a knock came at his door.

“Dimitri, may I come in?” the Professor asked. The young prince felt as if ice water had just been dumped over him for the second time today. Not now! Not when he was so close! He threw his hand on his bedside table, trying to steady himself.

Unfortunately he wound up creating a massive crater in the center with his fist. He felt the door handle begin to jingle as the woman on the other end tried to make her way inside to help him. And as much as he adored her, he imagined the feeling would never become mutual if she saw him naked, half hard cock in his grasp, covered in lotion.

“A-ah Professor! Yes… I… I need a moment.” He said, scrambling to put on clothes. His uniform took far too long, what with all its claps and buttons. He instead grabbed his sleeping clothes from underneath his bed. They were a bit inappropriate for meeting with an esteemed educator, but they cover the basics.

Before he opened the door he glared down at himself, willing his persistent erection to go away. The panic seemed to cause it to subside for now, but he still felt the painful urge to copulate. With a beautiful woman at his door. When they were all alone. 

He took a deep breath, put on his brave princely deminor and answered the door with a smile.

“I apologize! I was- Well I mean.” He wanted to kick himself. He couldn't even manage to form a sentence!? Of course how could he be expected to when his Professor was still dressed… like that. His hands itched to grab her hips.

“Dimitri. Show it to me.” She had such a severe expression, quite a distance from her usual blank face. His hormone addled mind played with the euphemism. Surely she wasn't talking about-

“... I’m sorry what.”

“You heard me.” Byleth said, arms crossed underneath her breasts. At this point Dimitri was convinced she was doing this on purpose. And since they were standing he was practically forced to look right down her shirt. This was too much.

“I’m afraid I don't know what you mean Professor.” He said, trying desperately to convey some confidence in his voice.

“Yes you do, show it to me.” She demanded, forcing her way inside, practically pushing him back with her. Oh goddess she smelled so good, Dimitri thought.

He needed something else to focus on, and quick before his raging problem came back. He looked at the mess he’d left in his wake. “I’m sorry for the state of my room… I was not expecting company.” 

“Dimitri. Please look at me.” She said in the same soft voice he remembered from the last time he was seriously hurt during a class excursion. He had no choice but to stand strong and hope his body would not betray him.

Her plea for his attention was reflected in her eyes. Dimitri always loved her eyes. The Professor always had difficulty expressing herself, but in those deep pools he could always find some glimmer of emotion. It made denying her anything next to impossible. Without a word his teacher removed her gloves and began to prod at the muscles on his chest.

She was touching him. This wasn't a dream. He could feel every callous on her finger make contact with his body. He froze, as if any movement would make her put the gloves back on and leave. She seemed to be studying him, every small movement she made she glanced up at him as if searching for a reaction. He willed himself not to give anything away.

Her hands on his chest were bad enough, but at least that was clothed. When she started exploring the muscles on his arms he could hardly breath.

“Uhm…” Dimitri whispered, trying not to break her trance.

“You hurt yourself didn't you?” The Professor asked softly. He wanted to crush her in his arms. Was she trying to perform a check up? He couldn't tell. He couldn't even think straight. All he could focus on was her soft touch.

“I… ah… I’m not… sure your meaning.” He murmured. He could handle her brief caresses. Soon she’d see there was nothing wrong with him and she’d leave then Dimitri could take out all his beastly urges on himself and still make eye contact with her tomorrow during class. It was fine.

Of course then Byleth Eisner dropped to her knees and all thoughts of maintaining etiquette flew out his brain. He looked down panicked. She was right there. All she had to do was look up and she’d see her effect on him plain as day. She’d never look at him the same way again. And then she started rubbing up his legs and he couldn't begin to care.

His mind was like a scale out of whack. He could only go from one extreme to the other. With every touch his Professor made him feel more and more like an animal in heat. He could feel his erection come back with avengence. This was not good.

Finally she rose up from her seated position and his heart stopped. Dimitri begged the goddess for absolution. It was better than looking down at his Professor, who was currently face to face with his quickly growing problem. Why had the goddess blessed him with such sweet agony. Or was this a punishment? He wasn't sure.

“Oh.” She said simply. Dimitri couldn't look at her. He couldn't face her after this. He’d throw himself from the top of the Goddess Tower as punishment, Kingdom be damned. He tried to make the words come. But his mouth stayed glued shut. The shame had not softened his erection. In fact his lust only seemed to increase.

The two stayed still for a full minute. Then another. Neither saying a word to each other, and only the sound of their breathing bouncing off the walls. 

“Do you want me to touch you?” His Professor whispered. Instead of words, he responded with a moan.

“Mm. Then thats a yes?” His teacher said, and before he could gather the strength to respond properly he felt something warm and wet rub his cock from outside of his trousers.

Dimitri let out a long, somewhat embarrassing, groan. He felt his face flush. Everything felt on fire. That must have been her tongue. Did she intend to-

“Dimitri sit on the bed.” She commanded, in the exact same voice she used when she’d direct him in battle. Stern but caring. He could only obey.

He slipped from her and fell back into the bed awkwardly. He must look like such a fool, all disheveled like this. She stalked to him, looking like a beautiful, vengeful goddess in the low candle light. He gulped hard.

“Is this what's been bothering you?” She asked, moving to kneel once again on the hardwood floor. The only difference is this time he could see her face. She looked at him with dark, curious eyes as she curled her head onto his lap. He could feel her breath right on his cock.

“..Yes.” He finally gasped out.

“Then why didn't you tell me?”

“Professor- I- I didn't think it was appropriate to.. Discuss such matters with you.”

“Why not?” She asked, in a tone that made it seem like they were talking about something as innocuous as the weather.

“Be-Because-” Because she was stroking his cock while staring at him. Because she was his mentor. Because she was the utter object of his desires.

“I want to help you with everything Dimitri.” she said, pulling her body up from the floor, rubbing herself all over him devilishly, until her breasts were pressed against his chest, their mouths only an inch or so apart. “Do you know why?”

He couldn't focus. Everything felt like simultaneously too much and not enough. “N-No.”

“Because you’re my favorite student.” She whispered, rubbing her thighs against his cock in a tortuous motion.

She moved her mouth to his neck, running her tongue up his jugular. Finally Dimitri felt some strength return to his limbs and he grabbed her hips. The tortuous flesh felt warm in his hands and he gave it a squeeze, causing his Professor to moan directly in his ear.

“Do it again.” She breathed. He knew it would be cruel to deny her when she begged so sweetly, but he did anyway, running his hands up her waist and onto her back, where the claps to her corset lay.

She let out a long whine, then adjusted her hips to lay directly on his cock. Dimitri threw back his head, solidly banging it on the wall he sat against. His teacher let out a giggle.

“I didn't know you could laugh.” He said, his voice strained.

“I’m sorry.” Byleth said with a smile. He couldn't help it anymore. He kissed her, wrapping his arms around her fully, smashing her against him.

“That was rough.” she gasped out between their lips.

“I-” Before the prince could even respond properly she slid her tongue into his mouth, a sensation so wonderful he could feel it in his bones. 

Dimitri had no experience with such matters, but judging from his Professors reaction he wasn't doing too bad. She excitedly rubbed her core against his cock and the friction made him see stars. 

Suddenly Byleth started wrestling against him, an act that made him think he’d pushed too far. She ended the kiss, painting desperately as she pressed their foreheads together.

“Did I do something wrong?” He whimpered. She shook her head and extracted herself from his grip to crawl off the bed.

This is it. He’d officially ruined everything. He must have done something wrong. He thought back in vain to all the love making advice Sylvain had foisted on him over the years. Had he forgotten something vital?

His worries were unfounded. He looked up just as his teacher dropped one of the gauntlets on her arms to the ground uncaringly. Then the other. She was stripping for him he realized with wonder.

Well a true gentleman doesn't just leave a lady to remove her own garments does he? A voice in his head (that sounded shockingly similar to his red headed confidant) asked. He stood up without thinking.

“Let me help.” He said, dropping to his knees as she had for him earlier to remove the plates sitting on her calves. He rubbed his face on her thighs as he wrestled the clasp. The first one fell. Then the next. His head bumped into the apex of her thighs and she sucked in her breath.

Dimitri looked up from his task. He seized her shapely legs and pressed his face to her center. Byleth moaned above him and wound her hands into his hair. He took that as his queue to examine her further.

He ran his tongue over the black mesh that covered her slit. He could feel her legs shake violently beneath his touch. He peered up above him. His teachers face was flushed, and she was groping her breasts as if in search of some kind of relief. She looked like just as much of a mess as he did and he relished it. 

“Professor.”

She groaned in response, meeting his eyes as he pushed himself up. She whined at the lack of contact, which he rectified by embracing her soundly. “Don't call me Professor.” She said, her voice muffled against his chest.

He ran a hand through her hair. “What should I call you then.” He teased, the rapid beat of his heart giving away how nervous he was.

“Byleth.” She told him, tilting her head up to meet his stare.

“Mhm. Alright Byleth. May I undress you?”

She responded not in words, but by shoving his own shirt up. He let out a bark of laughter and compiled, his mind still reeling that this was actually happening.

“Take off your pants.” 

“Yes ma’am.” He said, hurriedly stripping himself. Before long he was naked in front of her, and she ogled him unabashedly.

“Is- Is something wrong?” He asked, anxiously running a hand through his hair.

“... You’re big.” She said simply, her eyes wide.

“... Is that a bad thing?”

“Not at all.” The flush on her face spread to her chest, and suddenly Dimitr was reminded that he was the only one naked. He stepped closer to her and ripped her corset off, causing it to hit the floor with a bang. He was very grateful that everyone chose today as the day not to hang around the dorms.

Byleth’s breasts hung heavy, and before he could disrobe her further she huffed and pulled them out of the jumpsuit. He swallowed dryly and started at her bust in amazement.

“Dimitri.”

“Hmm?”

“Touch me.”

“Ahh uhm yes-” Impatiently Byleth lifted his hands from his side and fixed them onto her bosom. He reflexively squeezed and Byleth wailed. 

“More. Do that again but more.” She ordered. Dimitri complied, roughly manhandling the tissue, rubbing his thumbs against the erect nipples and she sobbed. Then he got an idea. He moved her closer to him and bowed his head, sucking one into his mouth. 

The Professors moans only increased as she pressed his head further into her chest. He took his free hand and searched her back frantically for the zipper that held her clothes together. Finally he found it and carefully pulled it down, conscious that she would eventually have to leave his room and needed to be wearing clothes for that.

Unfortunately.

He pulled away from her, releasing her breast with a loud pop that echoed through the room. Before she could protest he slid her arms out of the suit and dragged it slowly down her legs until she delicately stepped out of it. He looked her up and down carefully. He would never be so enamored with another. She was perfection.

Her hips and stomach were as wide and soft as it had felt through her clothes. Her thighs were thick and shapely and he wanted nothing more than to carve the flesh with his teeth. He should tell her she’s beautiful. That she’s the most immaculate thing he’d ever seen.

“Sit on my face.” He said instead.

She raised her eyebrows, and before she could respond he threw her over his shoulder and onto his bed. She landed with a little oof and before she could properly adjust herself Dimitri shoved his head between her legs.

Long ago he, Felix, Sylvain and Ingrid had been exploring his families massive library and stumbled upon a book. It was full of diagrams that made him feel all sorts of tingles that he at the time had no words to explain. Felix had insisted they put the book back, under the protest of Ingrid and Sylvain who wanted to know what was inside. Dimitri had at the time agreed, only to creep back down the stairs after everyone had gone to bed and read the whole thing in one sitting.

Inside it explained the exact anatomy of a woman, and how one would go about pleasing her. From ages twelve until sixteen that tome had been his only comfort on lost, hormone filled nights. He’d memorized every line, every word, every instruction like the fate of his kingdom rested in the balance.

Judging by the way Byleth was panting he’d managed to retain quite a bit from his studies. He experimentally licked every inch of her, rubbing tongue especially hard against the sensitive peak. Above him his Professor was twisting herself against his sheets, singing out his name like a prayer. 

He took one hand off her abused thighs and ran a single digit up her folds, penetrating her center. Byleth let out a sharp cry, reaching out to make some kind of contact with him. He trailed his other hand up her body, which she took in both of hers, squeezing it for the life of her. 

The position was a bit awkward, but the noises she made were all worth it. He slid another finger inside of her, pumping them furiously as he continued his attack on her clit. Her cries only grew louder and somewhere in the back of his mind he became wary that someone passing by would be able to hear them. But at the moment he didn't care. He matched the tempo until Byleth let out one last sob. He could feel her body tighten up, then release all over his fingers.

He pulled them out, then attached his mouth to her soaked hole, licking up any trace of her. She softly whimpered as he continued his ministrations. After he was satisfied he kissed up her stomach, between the valley of her breasts and her neck until finally he captured her lips. Byleth pulled him tightly against her while the two sloppily kissed, trading her essence with their tongues.

Dimitri couldn't have been happier. This is everything he ever wanted. His cock twitched, trapped against her stomach. Just a bit lower and he could be inside!

“Dimitri…” She said sweetly. “Your tongue is swollen.”

He laughed and pressed his face against her neck. “I suppose I should have expected that.”

“Mhm.”

The two laid in silence for a moment. Dimitri would have been perfectly happy to go to sleep right then but Byleth had other plans. She brought up her knee and began grinding against his cock. Startled, the young prince jumped from his respite in the crook of her shoulder.

“You don't have t-”

“I want to.” She said, eyes focused on him. The pressure was building up again.

“Wait- Mmm- Ah. B-Byleth please wait. I haven't- I mean I’ve never had the oppurtunity-”

“You’re a virgin?” She asked, with no shock in her voice as she reached a hand down and carressed the head of his cock. 

“Erm- Yes? Is that a problem?”

She released his member and wrapped both arms around his head. “Why would it be. I’m your teacher. I’ll teach you what you need to know.” She said softly, leaving a small kiss on his lips as he stared at her. He felt his erection pulse. This was too good to be true. It was his fantasy come to life.

“Wh-What are you going to teach me?” He asked, suddenly feeling quite green next to his experienced professor.

She smiled and adjusted him on the mattress, laying him down like he would be going to sleep for the night. She leaned down and kissed him.

“I’m going to teach you how to lie still when I put your fat cock in my mouth.” She said against his lips. Dimitri practically melted as she made her way down his body and did just what she promised.

Byleth sat on his thighs, legs bowed adorably as she pulled her hair back. When she bent over and made contact his whole body tensed. She smiled and licked a long strip on the underside of his member. Dimitri bit into the pillow beside him. Then to his delight and horror she pulled the whole thing inside her mouth.

She hummed around his cock, dutifully making circles with her tongue on his shaft. He gripped the headboard. There was no way he was going to be able to make this last.

“I’m not going to take much longer.” He gritted out, hearing the wood bending underneath his fingertips. Byleth eyed him, mouth still firmly attached with no signs of releasing him.

“You should probably.. You know… pull off.” He whispered. Byleth slowed, moaning around him. Then she sped up.

The sensation of someones mouth on your most sensitive spot was not what he expected. It was simultaneously hot and cold, creating delicious friction with every pump, every lick. He gasped, then looked down at the young woman who was currently palming his balls.

“Professor.. I...” He said, forgetting for the moment that she’d given him permission to say his first name. She seemed to respond to that, taking him deeper inside of her. He felt the familiar coil in his stomach that told him a climax was evident. Byleth seemed to notice, and pulled her mouth up to focus on his head, running tortuous circles around and around with her tongue. 

His climax rushed on him like a dam breaking. From the cloud of lust that formed around him he could see Byleth pulled off in time, allowing the strings of cum to hit her breasts rather than her throat. Dimitri felt spent, sinking back into the bed with a long sigh.

“Thank you.” He said, eyes half lidded as he watched his Professors chest fall and rise, still sticky with his seed. She swiped a finger curiously in the mix, then stuck it in her mouth. Just like that his lust came creeping back around. He groaned into his pillow, looking up at grooves he left in the wooden frame. That would be hard to explain.

“I was happy to do it.” Byleth said, moving to lay out on top of him, breasts mashed against his chest. 

He wrapped his arms around her, refusing to ask the obvious question of what they do now. He wanted to fall asleep just like this. Byleth tucked herself into his neck, worrying the flesh with love bites. It seemed the two were both united on not worrying about what comes after the afterglow. 

He took the opportunity to run his hands all over her. She was strong, he could feel the muscles on her back move underneath him. Her stomach was soft and round, covered in little scars from her years as a mercenary. He wanted to do this forever.

“Dimitri…” She said sleepily. “Please blow out the candles.”

He did just that, going about it like it was his nightly routine, the easiest thing in the world. He blew out the ones on his desk, and the one sitting on his chest against his bed. He was a little surprised that their rocking had not disrupted it. Quickly he flung himself back into bed, rolling onto his side to hold Byleth.

“Mmm… I’m cozy…” She muttered.

“Me too….” 

The two fell into a companionable silence, until Dimitri asked. “How will you get back to your room?”

Byleth sighed and turned around in his arms to face him. They both looked a mess. Sweaty, sticky and flushed. Even if she got fully dressed and left now there was no way she’d be able to sneak away without someone seeing. “I’ll wait until later. Right now I want to be held.”

“I’ll happily help you with that.” He said into her neck as the two faded into a warm, dreamless slumber.

While this certainly wasn't the first time Byleth woke up with someone wrapped around her, it was certainly the most memorable. Over the few hours they slept Dimitri had rolled on top of her, nestling himself into her chest, snoozing peacefully.

She fucked up. 

She fucked up so bad.

Seteth was going to hang her by her toes. Rhea was going to light her on fire. This must have been some kind of affront to the Goddess. Sleeping with not only her student but the Crowned Prince of the Holy Kingdom of Fargus? This was very bad.

“My my my. It seems someone acted on their crush.” Soothis taunted her from inside her head. Byleth groaned. She’d hoped her luck would hold out and the progenitor god would still be asleep and unaware of the world around her. 

Dimitri started to stir against her his hair tickling her as he breathed. Byleth cooled herself down. There was no use in giving into panic. Emotions were tricky as she’d learned in the past few months. She’d simply just let her lust dictate her. That was all it was.

She looked down at Dimitri, the full light of the moon shining on his features as he afixed himself to her breast. She felt a wave of affection for him. He somehow managed to both dangerously attractive and hopelessly charming at once. She knew she shouldn't have let things go so far but she couldn't seem to help it. Funny, she’d never had this problem before with her other lovers.

She experimentally rubbed her legs. Her thighs were sore from all the attention of Dimitris mouth. She could feel the spots where he’d bruised her holding him in his grip. For a virgin he certainly had an intensity about him. She burned thinking of his gaze while he relentlessly attacked her pussy. How his hands squeezed her breasts. She felt her libdo build again.

This is the part where she should be delicately slipping out of bed, getting dressed and pretending this had never happened. She could take him aside at a later date and explain that she was sorry she took advantage of him while he was aroused, and how she would never do it again. But as her body pulsed with craving she knew that would never work.

“Professor..” Dimitri mumbled into her breast, eyes squinting as he adjusted to the low light.

“Hello.” She said gingerly. He moved up to greet her with a kiss, a slow methodical thing. Nothing like the passionate saliva swapping they’d done earlier that night.

“I’m glad you’re still here.” He said against her mouth, his hands moving from underneath the blanket to grasp at her hips. She could feel an erection growing against her leg. He lightly thrusted it against her thighs, a motion that made her insides melt. 

“I’ll have to go soon.” She moaned against him, opening her legs.

“I know.”

Clearly he didn't know, Byleth thought, feeling his hand crawling south. Of course she wasn't helping by running her fingers down his spine. Her motivation to leave was quickly slipping away. 

“Dimitri…” She panted out as his lips moved to her neck.

“You can stay a bit longer can you? Please?” He pleaded into her skin. His fingers ran the seam of her cunt and she had to bite her lip to keep from moaning. The others were asleep now and the risk of getting caught was much greater.

She tilted her head away from him, if only to catch her breath. “I’ll need to go before anyone wakes up.” She whimpered, keeping her focus firmly on the smashed end table rather than the young man laying on top of her.

“I’ll do anything.” He begged between the onslaught of kisses he spread down her neck and chest.

Byleth couldnt breath. Her brain felt hot and foggy. Was it really so bad to stay for just a little while longer? She glanced down at Dimitri as he bit harshly into the tender flesh of her breast. She covered her mouth with both hands, praying that no noise would slip out. Unconsciously, her hips tilted upwards, giving her student the go to ravage her senselessly.

He smiled sweetly up at her and delicately slipped a finger inside. Byleth felt her whole body shake, until he another went in and all she could see were sparks against her eyelids. Her reaction seemed to light a fire under the prince. He picked up his pace and sucked at her skin to the point of bruising. She wouldn't be surprised to find out later that he drew blood, but frankly was too distracted to care.

Her orgasm was building. She looked down at Dimitri. His light hair was disheveled and his pupils were blown out. He crept toward her face, staring at her in such a single minded fashion she thought of beasts stalking their prey. With his free hand he shoved her limbs away and grasped her throat.

“Let me hear you.” He demanded, his voice rough.

“But the others-”

“I want them to hear.”

She shook her head furiously and in retaliation Dimiri rubbed the base of his palm aggressively against her clit. Unable to hold back she let out a long moan, meeting his hand.

“Good job Professor.” He whispered darkly, letting go of her neck and meeting her mouth with a kiss.

Byleth was floored. Her release came suddenly and she wrapped her arms around Dimitri as she tried to drown her moans in his shoulder. Slowly he pulled his fingers out and sat back against her stomach, his face looking somewhat triumphant. She shuddered, feeling the chill of his absence.

She propped herself up with her elbows and examined the man in front of her. Her work had left him littered with marks and his whole body glowed with sweat. She could feel his cock practically vibrate against her stomach. She could feel her mouth water. It felt so good she wanted it to be inside her, school and country be damned. She tried to sit up but Dimitri stopped her.

“I apologize for the.. I mean across your neck.” He motioned down her body, which was unsurprisingly covered in his handiwork. She felt something deep and feral inside her satisfied with the mess they’d made of each other.

“... Its okay.” Byleth said as her student slid out from on top of her to sit beside her, moving his sheet to cover the both of them. Apparently now he found their nakedness embarrassing.

“I’m also regretful of my behavior uhm… during.” He said awkwardly, trying to find the words to atone.

This was her out. This was where she could do the appropriate thing and escape, chalk it up to misplaced stress relief and have a mutually awkward relationship with the head of her house moving forward. But Byleth couldn't pull her eyes away from his cock, strained against the flimsy piece of fabric between the two. She could vaguely hear her student struggle to explain his actions.

“Uhm. Professor?” He asked, placing a hand on her leg.

“Dimitri.” She said suddenly with an intensity that even surprised herself.

“Yes?”

“I am going to leave this room.”

Her student nodded, disappointed but understanding.

“But before I do, I’m going to fuck you.”

He spluttered, eyes wide and bright red like the Dimitri she was used to. Byleth moved out of the sheet and sat on his still covered lap, pussy planted firmly on his length.

“I-I.. Are you sure?” He asked.

“Mhhm.” She said, moving her hips up and down his shaft. She saw Dimitris eyes roll back in his head and she smiled. People liked to call her a demon. Why not act like it once in a while?

“Bu-But you said you had to go.” he whimpered out, arms tightening around her while she continued her grinding.

“I do. But I want you first.” She whispered into his ear as her chin hooked over his shoulder.

In response her student moaned helplessly, his back hitting the wall he shared with Sylvain.

“You’ll have to be a good boy and be quiet.” She breathed into his ear, her tone heavy with arousal.

“I promise. I’ll be good.” He gritted out, eyes scrunched up. Byleth bit his ear lobe and he choked back a sob.

“Then I’m going to pull back this sheet and put your cock inside me. Okay?” She asked, giving his member another hard squeeze.

“Yes… Please… Yes.” He groaned. 

Byleth smirked and gave his throat one final nip, pulling back the sheet and grasping his member. She could see Dimitri bite his lip above her. In one easy motion she lined his cock up to her pussy and inched it inside. She pressed her forehead against his chest. He was thicker than she’d ever had before. She could feel him trembling against her, desperately holding in moans.

She felt impatient. She wanted him filling her now! She looked up from his chest. His adams apple was restlessly moving up and down his throat as he resisted letting any noise escape. She adjusted herself, grinding harder until finally she reached the base of his cock. She bit hard into his skin, feeling him hitting a spot she wasn't even sure until this moment she had. She heard something rip and looked down. Dimitri tore a hole clean through the mattress. She felt a fresh swell of adoration and pulled his head down to kiss him.

“I’m sorry I made noise.” He mumbled.

Byleth kissed his nose. “Its okay. May I start moving?”

“Goddess yes.” She laughed and pressed his chest down with both hands, ushering him to lie flat on his back. After adjusting slightly she started her slow, methodical movements up and down his cock. Dimitri gripped her hips tightly, trying to urge her to go faster. She instead relaxed her momentum, earning herself a harsh glare from her student.

“If you’re so displease you should try taking matters into your own hands.” She challenged.

He resented her defiance it seemed, lifting his hips to meet hers so roughly she nearly lost her balance. Byleth couldn't hold back the long whine that ripped through her. Dimitri was a quick study, and in her weakness he sat up and rolled her onto her stomach, pulling out with a sharp hiss.

“I’m sorry Professor, I’ll be taking over now.” He said darkly into her ear. She gasped when he re-entered her, his thrusts punishingly fast. She reached a hand down to rub her clit while Dimitri fucked the sense out of her.

She could feel his forehead against her back as he thrusted with reckless abandon. They both seemed to lose their original inhibitions, moaning loud enough for either of his neighbors to hear them.

“Byleth… I can't.. Not for much longer..” He panted out, nipping at the shell of her ear while he moved inside her.

“Its okay.” She gasped out, feeling each bruising thrust push her closer to her end. She sped up her movements with her fingers.

His groans grew faster, his tempo matching the pace as he reached underneath her to grab a breast. She cooed over his attentions, furiously circling that sweet spot.

“Dimitri. Kiss me.” She demanded. He let out an airy chuckle and moved to meet her lips. She could feel everything tighten, and finally she met her limit. 

Dimitri gasped, feeling her squeeze around his cock, and in one final motion he pulled himself out of her, falling against her as his cum shot between them. 

The two laid their, soothed by the feeling of their feverish skin cooling. Finally Dimitri broke the silence.

“I didn't mean to… you know… on your back.” He told her.

“It's alright. Better there than in me.” she said, rolling over to meet his eyes.

“Would it be inappropriate of me to ask what we’re going to do after this?”

“Well. I’m going to get dressed. Then I’m going to walk back to my room. I doubt I’ll be able to sleep here.” She teased.

“No I mean. With classes and the academy and what not.”

“Ah I see your princely manners have returned.”

“Are you. Are you actually joking around with me?” he asked incredulously.

“Am I?” She said, a serious look on her face.

“I- You know what nevermind. Maybe I should kiss you in front of the whole class, that would certainly show Sylvain a thing or two.”

Her eyes widened. “You wouldn't.”

“Would I?” He asked raising an eyebrow. Oh… So he was joking with her now. She flicked his forehead.

“Are you bullying me Professor?” He asked, rubbing the spot on his head.

“Yes.” She said with just the slightest hint of a smile. He moved to pull her closer to him, then glanced out the window.

“Oh no.” 

“What?”

“Making your escape might prove to be more difficult now.”

Curiously she whipped her head around to the large window. In all their…. Activity both parties had failed to realize the sun was rising, and people would be waking up soon. Byleth stood up and began searching for her lost clothes.

“Oh let me help you.” Dimitri said, moving to scour the floor with her. Finally they managed to wrangle her suit, armour plates and corset. She looked down and frowned.

“I have no idea how to put this on.” She said to the offending garment.

“I’ll help you with that as well.” The prince said as his put on the trousers they abandoned last night.

Between the two of them they managed to get her looking somewhat presentable. As she attached her breast plate she heard Dimitri behind her.

“Oh.” He said, holding her corset out for her to look at. 

It seems Dimitri managed to rip whole chunks of the binding out when he tore it off of her last night. Byleth raised both eyebrows in amazement.

“I’ll pay for a replacement of course.” He said quickly. She smiled and placed a kiss on his lips.

“It’s alright. I have four more coming next week.” She said, pulling her gloves on while her student stared dumbly at her.

“Would it be appropriate to walk you back to your quarters?” He asked.

Byleth shook her head. The last thing she needed were people to make assumptions, no matter how correct those assumptions might be. “I’ll see you in class Dimitri.” she said, and before he could respond she slipped out the door.

Lucky for her the hallway was clear. She managed to make her way downstairs with no one in sight. She eyed her room but chose to walk past it. She felt too invigorated to coop herself inside for the next few hours before classes begin. She took a walk through the gardens, admiring the bright gold the trees had turned for the harvest season.

Finally she made her way to the Greenhouse, intending to burn off some excess energy by pruning the plants. But someone was already inside.

“Good morning Professor.” Dedues deep voice said from his kneeling position on the floor. Of course he would be up this early.

“Hello. May I join you?” 

He grunted in response. The two sat together in mutual silence for a few minutes.

“Have you had a chance to speak to His Highness yet?” He asked. She felt a twinge of anxiety burrow itself in her stomach. Surely he wouldn't have discovered them?

“Yes. I did last night.”

“Thank you.”

“Of course.”

The two continued their work until sunrise. Byleth, satisfied with the results, stood up to get breakfast.

“One last thing Professor.” She turned and looked at her student curiously.

“Please don't make a habit of staying overnight in His Highness's room. He may never sleep again.”

“How did you-” Dedue nodded downward, Byleth followed his gesture to her chest, where a litter of hickeys were resting right in her eyeline.

“Oh.”

**Notes for the Chapter:**

> SOOOOO HOW'D WE LIKE IT? Any comments? Criticisms? Please write me in the comment box bellow, I love to learn and grow as a writer and you all help me with every message.
> 
> I want to give a special shout out to my beautiful darlings on the dimileth discord server! They all listened to me freak out over edits and writing and even read through my first draft! If you'd like to join please let me know and I'll pass along the link.
> 
> I'm thinking about making this something of a series with all my favorite BL ships. Would anyone like to see that with my other ships? Please let me know!
> 
> So, that's through thicc and thin! Thank you all so much for reading it!
> 
> P.S. Sylvain and Felix didn't hear them at all because they were both in Ingrid's room having a threesome.


	3. Part Three: A sequel announcement!

**Summary for the Chapter:**

> Day Seven of Dimileth Week. Sequel to Through Thicc and Thin. 
> 
> Its been two weeks since Byleth and Dimitris late night tryst and both have been staunchly avoiding discussing what happened. But when the Professor shows up to dinner wearing a dazzling pair of specs he finds it difficult to hold the stalemate.

Hi everyone! Thank you all so much for supporting TTaT! It's by far my most popular fic to date. I wanted to give a brief update here to let you all know that I wrote a sequel in honor of Dimileth Week!

For those who weren't aware September 22nd-September 28th is Dimileth week and I wrote seven fics for it. The last prompt was ‘free day’ so I figured what better way to thank everyone for their support than to create a sequel? Its my most recent fic as of September 28th so please pop over to my page and check it out! 

The title is ‘Through the Looking Glasses’ in reference to Byleths new DLC look. Please enjoy!

**Author's Note:**

> Soooo..... This was originally going to be a one-shot but I had way too many ideas on where to go with it, so surprise! It's going to have at least two chapters. Please give kudos and comments! It helps me write and gives me great joy!


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